There's a lot of passion on display in American Conservatory Theater's "The Orphan of Zhao," especially when it comes to self-sacrifice for the greater good, but that's just the problem. The passion is displayed rather than felt.

The audience is kept at a certain distance from the emotion of this eventful story, and part of that comes from James Fenton's adaptation of "Zhao," a Chinese tale that stretches back for millennia. Fenton's language has a purposefully formal, ancient feeling to it even though he created the play for the Royal Shakespeare Company in 2012.

Director Carey Perloff's production (in association with La Jolla Playhouse in San Diego County, where the show reopens next month) also comes across more as pageant than play, and that diminishes the visceral impact that should be building through the show's nearly 2 1/2 hours.

Certain elements of that pageant are quite enjoyable, most notably the original score by Byron Au Yong and played by an onstage cellist and violinist augmented by cast members on percussion and unusual instruments (like water bowls). Some of the songs feel organic to the tale, while others come off as second-rate Sondheim.

Juicy revenge tale

Linda Cho's costumes add an element of pomp without being overly fussy except when they need to be, as in the case of a demented princess locked in a crumbling palace.

"The Orphan of Zhao" is, at heart, a juicy revenge tale. Once we get to the actual revenge part, the production gains some much-needed traction, but that doesn't happen until Act 2. The whole first act is setup, and it feels mighty long in spite of a heartfelt performance by San Francisco native and Tony winner BD Wong as Cheng Ying, a country doctor whose life is forever changed by making a house call to the savage palace of the emperor.

A minister in the emperor's court (Nick Gabriel as Zhao Dun) has the courage to tell the callow ruler (Paolo Montalban) the truth: The nefarious Tu'an Gu (Stan Egi) wields far too much power over the emperor and his court. Branded a traitor, the minister is forced to die at his own hand, and 300 members of his clan are slaughtered.

His newborn son and only surviving heir is secreted away by the country doctor in the hope that the child will one day discover who he really is and take revenge.

By Act 2, 18 years have gone by, and we meet Cheng Bo (the charismatic Daisuke Tsuji), the "orphan of Zhao" who has been safely raised in the bosom of the court and considers Tu'an Gu, the man who destroyed his family, as a second father.

Strong supporting cast

It's a sprawling tale, and Daniel Ostling's towering bamboo scaffolding set allows for a smooth flow of scenes and locations even if it seems to overwhelm the action at times. And there's some excellent supporting work in the ensemble, including Brian Rivera as a vicious dog known as the Demon Mastiff, and Orville Mendoza as Wei Jiang, a patient and morally upright general.

"Zhao" has been called the Chinese "Hamlet," and it's easy to see the parallel (son taking revenge on father's death), and once Cheng Bo, who was "born for a bloodthirsty destiny," begins to see the truth about himself and his country, this ancient game of thrones finally becomes compelling.